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Light-emitting device and method for making the same

a technology of light-emitting diodes and light-emitting diodes, which is applied in the direction of semiconductor devices, basic electric elements, electrical apparatus, etc., can solve the problems of short-circuiting of light-emitting diodes, reducing light extraction efficiency, and considerably limited light-emitting diodes

Active Publication Date: 2011-02-15
LITE ON TECH CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The solution significantly improves light extraction efficiency, with optical power output and light extraction efficiency increased by forming nanorods with a length of at least 200 nm and a protective layer, achieving up to 280% improvement in light intensity compared to conventional devices.

Problems solved by technology

It is known in the art that light extraction efficiency of a light-emitting diode is considerably limited due to the laminated layered structure of the light-emitting diode, which can cause total internal reflection of light generated from an active layer of the light-emitting diode, which, in turn, can result in a decrease in the light extraction efficiency.
However, in UV, blue, or green light emitting diodes, since the p-cladding layer thereof is relatively thin, which has a layer thickness required to be not greater than 200 nm, surface roughening of the same tends to cause short-circuiting of the light emitting diode and has an adverse effect on the electrical properties of the light emitting diode.
Although the light-emitting diode thus formed can enhance the light extraction efficiency, manufacturing of the same is complex and expensive.

Method used

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  • Light-emitting device and method for making the same
  • Light-emitting device and method for making the same
  • Light-emitting device and method for making the same

Examples

Experimental program
Comparison scheme
Effect test

example 1

[0037]The light-emitting device of Example 1 was prepared by the following steps.

[0038]First, an epitaxial layered structure 1, which includes a n-type GaN semiconductor layer 12, an active layer 13 (a multi quantum well having ten pairs InGaN / GaN), and a p-type GaN semiconductor layer 14 having a layer thickness of about 200 nm, was grown on a sapphire substrate 11 (Al2O3) having a diameter of 2 inches and a layer thickness of 500 μm through metal organic vapor phase epitaxy (MOVPE) techniques.

[0039]It is noted that formation of the epitaxial layered structure can also be conducted by molecular beam epitaxy (MBE) techniques or hydride vapor phase epitaxy (HVPE) techniques.

[0040]Subsequently, a current diffusion layer 15 made from ITO and having a thickness of approximately 200 nm was deposited on the p-type GaN semiconductor layer 14 by e-beam evaporation. A reflective layer 16 made from Al and having a thickness of approximately 500 nm was deposited on the current diffusion layer ...

example 2

[0047]The light-emitting device of Example 2 was prepared by steps similar to those of Example 1, except that the etching time was about 5 minutes and that the nanorods 41 thus formed had a length of approximately 1000 nm.

simulation example 1

SE1

[0055]In this simulation, the parameters set for the light-emitting device having a structure shown in FIG. 12 are as follows: The semiconductor material was GaN. The p-type semiconductor layer 14 has a layer thickness of 200 nm. The active layer 13 has a layer thickness of 200 nm. The n-type semiconductor layer 12 has a layer thickness of 2 μm (including the length of the nanorods 41). The nanorods 41 have a length of 200 nm. The protective layer 81 has a portion disposed above the free ends 42 of the nanorods 41 and having a thickness of 2 μm.

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Abstract

A light-emitting device is capable of emitting a light having a wavelength ranging from 300 to 550 nm, and includes: a substrate; a p-type semiconductor layer disposed on the substrate; an active layer disposed on the p-type semiconductor layer; a n-type semiconductor layer disposed on the active layer and having a waveguide-disposing surface; and a waveguide structure formed on the waveguide-disposing surface of the n-type semiconductor layer and having a plurality of spaced apart nanorods extending from the waveguide-disposing surface.

Description

CROSS-REFERENCE TO RELATED APPLICATION[0001]This application claims priority of Taiwanese application no. 096126350, filed on Jul. 19, 2007.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]This invention relates to a light-emitting device, more particularly to a light-emitting device including a waveguide structure having a plurality of nanorods formed on a n-type semiconductor layer.[0004]2. Description of the Related Art[0005]It is known in the art that light extraction efficiency of a light-emitting diode is considerably limited due to the laminated layered structure of the light-emitting diode, which can cause total internal reflection of light generated from an active layer of the light-emitting diode, which, in turn, can result in a decrease in the light extraction efficiency. Conventional methods for enhancing light extraction efficiency normally involve increasing surface roughness of the laminated layered structure of the light-emitting diode so as to reduce ...

Claims

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Application Information

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Patent Type & Authority Patents(United States)
IPC IPC(8): H01L21/00H01L33/10H01L33/14H01L33/32
CPCH01L33/20H01L33/10H01L33/44
Inventor CHIU, CHING-HUAHUANG, HUNG-WENKUO, HAO-CHUNGLU, TIEN-CHANGWANG, SHING-CHUNGLAI, CHIH-MING
Owner LITE ON TECH CORP